PRB Articles

Apr 3 Diverting A Disaster

The City of York, Neb., was founded in 1870 by the South Platte Land Company primarily as a reference point for Oregon, California and Mormon trails. It grew steadily, in part because of the then booming railroad industry.

“The community center was built in 1964 and included the museum,” said Paul Christensen, director of the YorkParks and Recreation Department. “A local businessman offered a challenge grant to expand the facility by adding a recreational center, thereby having everything in one location.”

In all, the final building design included the museum, office space, a gymnasium, racquetball courts, a cardio/weight room, locker room and an indoor pool. While this seemed a good idea to co-locate the pool in the same building with the museum, it would later prove to be an uncomfortable and costly decision.

Mounting Complaints

The museum contents included many one-of-a-kind items from the town’s history, such as articles from past wars fought by York soldiers, old farm machinery, a cavalry covered wagon, plus a multitude of clothing and paper items from all walks of York life. Over the years, the museum staff began to notice a gradual deterioration of artifacts. Sensitive items, like paper, began to disintegrate or became too delicate to handle. In addition, visitors and workers at the center were complaining of problems with temperature and humidity, as well as noise from the HVAC mechanical system. All eyes were directed at the pool as the problem source.

Orville Davidson, director of public works for the city, commented, “There were problems as well in the gymnasium/pool section with high humidity levels, making it uncomfortable to swim or exercise. Temperature varied throughout the facility, and the cost of heating the building rose rapidly as the price of energy began to escalate.”

Exploring Options

Recognizing the need to address the issues, the city leaders spoke with HVAC contractors to find a remedy, but quickly discovered the cost to modify the existing system too high and probably inadequate. They chose to bring in an architectural firm to study the problems and make recommendations.

The Clark Enersen Partners, an architectural/engineering firm in Lincoln, Neb., was chosen to complete the study. “The inside of the structure was sweating and rusting,” said Adam Kent, mechanical designer for the firm. “The system relied on inefficient fan coils and a multi-zone system that was costly to operate.”

The original HVAC arrangement consisted of two air-handling systems--one unit serving the museum and office areas and the other serving the pool, gymnasium, courts and support rooms. At 40 years old, both systems were past their prime and well past the American Society of Heating, Refrigeration and Air Conditioning Engineer’s estimated useful life for such units.

Both units were three-zone systems equipped with heating and a 100-percent economizer function, but only the museum unit had air conditioning. That system was not capable of cooling below 65 degrees, leaving that part of the facility uncomfortably warm and high in moisture. And it was the high moisture content that was chiefly responsible for the artifact deterioration.

Since the unit servicing the pool area had no air conditioning component, it relied on 100-percent ventilation to remove excess moisture. This was a common practice before the 1970s because mechanical dehumidification was not as sophisticated or popular as it is today. Indoor pool structures maintained comfortable conditions by ventilating moist air, replacing it with cooler, low-moisture outside air and heating as needed, with low-cost fossil fuels. What no one realized at the time was how the cost of energy would soar or how the migration of pool moisture to the museum section would overload the air conditioner, damaging the museum’s contents.

After completion of the study, Clark Enersen Partners provided recommendations for upgrading the HVAC mechanical equipment, and included an option to install a dehumidification system designed specifically for indoor pools.

Devising A Plan

As with any municipality, money was an issue. The city could not afford to make large capital improvements to the building such as space reconstruction, or run new duct work. Likewise, it did not want to install an oversized HVAC system to compensate for the ever-present pool moisture that would eventually tax the main system. The decision was made to dehumidify the pool room.

The first choice for mounting a dehumidification system for this project was on the roof. Clark Enersen Partners discovered the building structure would not support the extra weight. And because the original building design did not take into account the need for larger HVAC equipment, the mechanical room was too small to accommodate a large unit. PoolPak International was able to recommend two smaller PoolComPak units to handle the load without difficulty and without modification of the existing space and ducting.

The pool dehumidification systems selected were two PoolPak International PoolComPak AWV 2600 models. These units are designed specifically for the harsh, corrosive pool environment, controlling both temperature and humidity independent of the rest of the center.

Installing the PoolComPak had other advantages. As the unit dehumidifies the pool room, it recycles energy into the pool water or space as needed. That means less energy is needed to maintain a desired pool water temperature of around 80 degrees Faherenheit. Energy is also saved by eliminating the need to continuously heat large quantities of make-up air from constant ventilation.

The PoolComPak dehumidification system allows the facility to meet code requirements for energy use and ventilation. It is designed to operate under a negative-pressure condition, preventing the migration of pool air to the rest of the facility. The PoolComPak’s microprocessor controller manages space dew point, eliminating the formation of condensation on cold walls, windows and other surfaces.

As for the results, “The PoolPak system has met our expectations for stabilizing the atmosphere within the community center,” said Davidson. “This is a very difficult environment to control due to the very large amount of humidity. The system was retrofitted into existing space without any significant building modification, and we realized over a 15 percent reduction in electrical and gas combined consumption for fiscal year 2006-2007.”

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